Collecting this in one place because it comes up every few weeks and the answer is always assembled from scratch. It is about the glucagon co-agonists, and it is deliberately narrow — everything I am not confident about is marked as such.
What is actually established
The glucagon co-agonists — survodutide, mazdutide, ecnoglutide — are all chasing the same idea: add energy expenditure to appetite suppression. The liver signal is where they look strongest, because hepatic fatty-acid oxidation responds to glucagon directly rather than as a consequence of weight loss.
The condition it depends on
Worth remembering these are at different regulatory stages in different regions, and a phase 2 result in one jurisdiction is being quoted here as if it were a global standard of care.
What I am not sure about
What would genuinely help is knowing whether the liver signal is independent of weight loss or downstream of it, because that determines whether any of this is interesting for someone whose weight is already where they want it. Practical detail welcome, however dull — the duller the better.
— gary_naperville · corrections welcome and will be edited into this post with credit